Effect of Ashwagandha Supplements on Stress and Anxiety

A root used in Indian medicine for 3,000 years is now showing up in peer-reviewed journals with numbers that are hard to ignore — and the science behind why it works on stress and anxiety is more interesting than the supplement label lets on.

Quick Take

Multiple meta-analyses show ashwagandha significantly lowers anxiety scores and cortisol levels compared to placebo in adults.
Clinical trials have cut anxiety scores by 41% and dropped cortisol by as much as 28% in stressed adults.
An international medical task force now provisionally recommends 300–600 mg daily for generalized anxiety disorder.
Long-term safety beyond three months is still unknown, and people with liver or thyroid conditions face real risks.

The Ancient Herb That Keeps Showing Up in Modern Clinical Trials

Ashwagandha is a small shrub native to India and North Africa. Its root has been used in Ayurvedic medicine for thousands of years. What changed recently is that Western researchers started running rigorous, double-blind, placebo-controlled trials on it. The results keep pointing in the same direction. A 2024 meta-analysis published in BJPsych Open found that ashwagandha significantly reduced anxiety scores on the Hamilton Anxiety Rating Scale, cut perceived stress scores, and lowered cortisol levels — all measured at eight weeks of treatment. ^[1]

A separate meta-analysis of nine studies covering 558 participants found the same pattern. Ashwagandha beat placebo on stress, anxiety, and blood cortisol levels. Daily doses in those studies ranged from 125 to 600 mg over 30 to 90 days. ^[2] That kind of consistency across independent research teams is what separates a real signal from a lucky result.

How It Actually Works on Your Stress System

Ashwagandha does not work like a sedative. It does not knock you out or numb your brain. Instead, it appears to calm the hypothalamic-pituitary-adrenal axis — the command chain your body uses to release cortisol when you feel threatened. Clinical trials show it lowers cortisol in stressed adults by 23 to 33 percent. ^[3] Think of it as turning down the volume on your body’s alarm system rather than cutting the wires. That is why people report feeling calmer without feeling foggy.

One well-designed 60-day trial found that anxiety levels dropped by 41 percent in the ashwagandha group versus 24 percent in the placebo group. ^[4] Those numbers come from the Hamilton Anxiety Rating Scale, a validated clinical tool used in drug trials. The cortisol drop in that same study was measurable in blood tests, not just self-reported feelings. That matters. Subjective mood surveys are easy to game. Cortisol in your blood is not.

What the Medical Establishment Is Starting to Say

The National Institutes of Health now acknowledges that ashwagandha extracts may reduce stress, anxiety, and cortisol. ^[5] More notably, an international task force formed by the World Federation of Societies of Biological Psychiatry and the Canadian Network for Mood and Anxiety Treatments has provisionally recommended 300 to 600 mg of ashwagandha root extract daily for generalized anxiety disorder. ^[5] That is not a fringe wellness blog making that call. Those are mainstream psychiatric organizations.

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decreases the stress hormone cortisol, which decreases testosterone. Take 300–600 mg per day (KSM-66 is the finest form).

According to studies, testosterone levels grow significantly within 60 days. Increased energy, less anxiety, and…

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Mayo Clinic has weighed in too. Their guidance confirms that ashwagandha is the most studied area of the plant’s use and that improvements in both stress scores and cortisol levels have been documented. ^[8] They also note that the supplement may help anxious people sleep better — not by causing drowsiness directly, but by calming the mental noise that keeps people awake. For anyone over 40 who has stared at the ceiling at 2 a.m. with a racing mind, that distinction is worth understanding.

The Real Risks You Should Not Skip Past

The honest version of this story includes the gaps. The National Institutes of Health is clear: ashwagandha appears safe for up to about three months, but evidence on long-term use over many months or years is simply missing. ^[5] Most trials were small and ran only six to eight weeks. That is enough to show a short-term signal. It is not enough to know what happens to your liver or thyroid over two years of daily use.

Liver risk is the concern worth taking seriously. There are documented cases of liver injury linked to ashwagandha supplements. People with existing liver conditions — fatty liver, hepatitis, or anyone taking medications that stress the liver — should avoid it. ^[10] Thyroid concerns also exist, since ashwagandha may raise thyroxine levels, which matters for anyone already managing a thyroid condition. Pregnant women should not take it at all. The Food and Drug Administration has not reviewed or approved ashwagandha for safety or effectiveness. ^[12]

The Smart Way to Think About This Supplement

Ashwagandha sits in a rare category for dietary supplements. Most supplements, when put through rigorous trials, show no benefit. ^[19] Ashwagandha keeps showing a measurable, consistent effect on real biological markers. That earns it serious attention. But serious attention is not the same as a green light for everyone. The right approach is to treat it as a short-term tool, use a product standardized to withanolides, stay at 300 to 600 mg daily, and talk to a doctor first if you have any liver, thyroid, or medication concerns. ^[8] The science is genuinely promising. The long-term story is still being written.